Tough action to analyse. Most of the block support comes from the bottom of the loading trough.
This would cause the block to pivot like a Winchester low-wall.
The high walls provide little support due to outward bulging.
Think I can see bulge gaps at the top of the high walls on the rifle SKB shows.
Believe de Hass provided full support for the round block above and below the bore center-line.
JMHO, Chuck